1. Field of the Invention
This invention relates to a method of inserting a slide into a frame of elastic plastic, comprising expanding said frame on two opposite sides.
2. Description of the Prior Art
German Patent Specification No. 1,214,898 and corresponding U.S. Pat. No. 3,341,960 show in FIG. 8, and in FIG. 14, respectively, a slide frame having an entrance slot which merges without a transition into a tubular pocket for receiving the slide. The tubular pocket defines not only one entrance slot at one end but also another entrance slot at the opposite end. To hold the slide in the tubular pocket, limiting cams and grooves are provided at the top and bottom sides. Limiting cams and grooves are provided for lateral guidance of the slide. Further means for guiding the slide being inserted comprise bores, through which pins of a mounting machine are inserted to provide stops for guiding the slide.
In the remaining embodiments in the printed publications mentioned above each slide frame is formed with a pocket that is closed at one end so that additional features are required to permit a movement of the slide to a position for projection, i.e., to the closed end of the pocket, in spite of the inevitable deflection of the slide. That additional feature resides in that that end of the picture gate which is opposite to the entrance slot is beveled in an outward direction. In plastic frames which are made by extruding, stamping and glueing, the additional feature resides in that that edge of the picture gate which is opposite to the entrance slot is V-shaped in the plane of a plastic sheeting.